AS 1141.35:2019 pdf download.Methods for sampling and testing aggregates Method 35: Detection of sugar contamination in concrete aggregates.
4 TERMS AND DEFINITIONS
For the purposes of this document, the terms and definitions given in AS 1141.1 shall apply.
5 SAFETY PRECAUTIONS
Procedures using concentrated mineral acids, including the preparation of dilute solutions of these acids, shall be carried out in a fume cupboard.
Appropriate documentation for the mineral acid in use should he consulted as to safety precautions.
WARNING: CONCENTRATED ACIDS AND STRONG ALKALIS ARE HAZARDOUS AND CAN RESULT IN POTENTIALLY IRREVERSIBLE DAMAGE TO THE SKIN OR EYES. INGESTION OF THE CHEMICALS, INHALATION OF THE VAPOUR, OR SKIN CONTACT, CONSTITUTE A SERIOUS HEALTH HAZARD.
6 APPARATUS AND MATERIALS
The following apparatus, conforming to the relevant requirements of AS 1141.2, is required:
(a) Balance of suitable capacity, with a limit of performance of ±0.05g.
(b) Filter paper—white, double fine grade.
(c) Fume cupboard.
NOTE: Advice on suitable fume cupboards can be found in AS 2243.8.
(d) Glassware—beakers, measuring cylinders and filter funnels.
(e) Litmus paper.
7 REAGENTS
All reagents shall be of analytical grade. Distilled or dc-ionized water shall be used for all stages of the test. Reagents shall be specified by name or formula and shall consist of the following:
(a) !-1vdrochloric acid (HCI) (density = 1 .16 kg/L).
(b) Copper sulfite (CuSO4.5H20).
(c) Sodium hydroxide (N aO H).
(d) Sodium potassium tartrate (KNaC4H4O6.4H 20) (Rochel le salt).
8 TEST PORTION
By coning and quartering, or using sample dividers, take a test portion of approximately
100 g from a laboratory sample obtained in accordance with the procedures of AS 1141.3.1.
The test portion shall be used in the condition in which it was received.
9 SOLUTIONS REQUIRED
Prepare solutions as follows:
(a) Solution A: Dissolve 17.3 g of CuSO4.5H20 in water, and dilute the solution to 250 rnL.
(b) Solution B: Dissolve 30 g of NaOH in water and warm the solution. Dissolve 86.5 g of Rochelle salt in the warm NaOII solution. Cool the solution and dilute to 250 mL.
(c) Fehling’s solution: Mix equal volumes of Solution A and Solution B to make Fehling’s solution. This solution is used for detection of sugar. Fehling’s solution must be made immediately before use. It is not stable and must not be kept for more than 12 h.
(d) I M HCI: To 600 mL of water in a graduated flask or graduated cylinder, add 89.9 mL of the concentrated HCI and make up the volume to 1 L.
(e) I Al NaOH: Dissolve 40.Og of NaOH in water and make the volume up to I L.
10 TEST PROCEDURE
The procedure shall be as follows:
(a) Place a test sample of approximately 100 g of aggregate in a 250 mL beaker and cover it with water. Add 50 mL of I M ITCI and boil the mixture for 5 mm, then filter while still hot.
(b) If the filtrate is acid to litmus paper, cool 5 mL of it, neutralize it with I M NaOH solution and remove any precipitate by filtration. Add 3 mL of Fehling’s solution, thoroughly stir the resultant mixture, and heat it in a boiling water bath for 5 mm.
(c) If sugar is present, a reddish-brown precipitate will be formed.
(d) If the original filtrate is not acid to litmus paper, add a further 50 mL of 1 M HCI and boil the mixture for a further 5 mm (this should ensure that the filtrate is acid to litmus paper), then continue as in Step (b) for a filtrate that is acid to litmus paper.
NOTE: For this test it is intended that the filtrate be acid to litmus paper. A neutral or alkaline reaction indicates that the HC1 has been neutraLized by carbonates in the aggregate. This condition must be corrected by adding 11(1 and boiling the mixture.
11 TEST REPORT
The following shall be reported:
(a) The sampling procedure used.
(b) Sample identification.
(c) The test date.
(d) The presence or absence of sugar [see Clause l0(c)].
(e) The number of this Australian Standard, i.e., AS 1141.35. AS 1141.35 pdf download.